1PJZ

Solution structure of thiopurine methyltransferase from Pseudomonas syringae


Experimental Data Snapshot

  • Method: SOLUTION NMR
  • Conformers Calculated: 20 
  • Conformers Submitted: 20 
  • Selection Criteria: target function 

wwPDB Validation 3D Report Full Report


This is version 1.2 of the entry. See complete history

Literature

Tertiary structure of thiopurine methyltransferase from Pseudomonas syringae, a bacterial orthologue of a polymorphic, drug-metabolizing enzyme

Scheuermann, T.H.Lolis, E.Hodsdon, M.E.

(2003) J.Mol.Biol. 333: 573-585


  • PubMed Abstract: 
  • In humans, the enzyme thiopurine methyltransferase (TPMT) metabolizes 6-thiopurine (6-TP) medications, including 6-thioguanine, 6-mercaptopurine and azathioprine, commonly used for immune suppression and for the treatment of hematopoietic malignancie ...

    In humans, the enzyme thiopurine methyltransferase (TPMT) metabolizes 6-thiopurine (6-TP) medications, including 6-thioguanine, 6-mercaptopurine and azathioprine, commonly used for immune suppression and for the treatment of hematopoietic malignancies. S-Methylation by TPMT prevents the intracellular conversion of these drugs into active 6-thioguanine nucleotides (6-TGNs). Genetic polymorphisms in the TPMT protein sequence have been associated with decreased tissue enzymatic activities and an increased risk of life-threatening myelo-suppression from standard doses of 6-TP medications. Biochemical studies have demonstrated that TPMT deficiency is primarily associated with increased degradation of the polymorphic proteins through an ubiquitylation and proteasomal-dependent pathway. We have now determined the tertiary structure of the bacterial orthologue of TPMT from Pseudomonas syringae using NMR spectroscopy. Bacterial TPMT similarly catalyzes the S-adenosylmethionine (SAM)-dependent transmethylation of 6-TPs and shares 45% similarity (33% identity) with the human enzyme. Initial studies revealed an unstructured N terminus, which was removed for structural studies and subsequently determined to be required for enzymatic activity. Despite lacking sequence similarity to any protein of known three-dimensional structure, the tertiary structure of bacterial TPMT reveals a classical SAM-dependent methyltransferase topology, consisting of a seven-stranded beta-sheet flanked by alpha-helices on both sides. However, some deviations from the consensus topology, along with multiple insertions of structural elements, are evident. A review of the many experimentally determined tertiary structures of SAM-dependent methyltransferases demonstrates that such structural deviations from the consensus topology are common and often functionally important.


    Organizational Affiliation

    Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06520-8114, USA.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
Thiopurine S-methyltransferase
A
203Pseudomonas syringae pv. pisiMutation(s): 0 
Gene Names: tpm
EC: 2.1.1.67
Find proteins for O86262 (Pseudomonas syringae pv. pisi)
Go to UniProtKB:  O86262
Experimental Data & Validation

Experimental Data

  • Method: SOLUTION NMR
  • Conformers Calculated: 20 
  • Conformers Submitted: 20 
  • Selection Criteria: target function 
  • Olderado: 1PJZ Olderado

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2003-10-14
    Type: Initial release
  • Version 1.1: 2008-04-29
    Type: Version format compliance
  • Version 1.2: 2011-07-13
    Type: Version format compliance